perf(controller): tune nodescan controller cache

[fabriziosestito]

Description

Fixes #1177

[Copilot]

Pull request overview

This PR optimizes the controller-runtime cache configuration for node-scanning mode by stripping unneeded fields from cached Node and NodeSBOM objects, reducing memory usage in line with Issue #1177.

Changes:

• Added a TransformStripNode cache transform to retain only node OS/architecture (plus metadata) while clearing Spec, most of Status, and managed fields.
• Added unit tests covering the new node transform behavior.
• Enabled per-object cache transforms (and disabled deep-copy for read-only access) for Node and NodeSBOM when cfg.NodeScan is enabled.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
internal/controller/transform.go	Adds TransformStripNode to strip Node objects down to OS/arch + minimal metadata for cache efficiency.
internal/controller/transform_test.go	Adds unit test validating the node transform removes expected fields while preserving OS/arch and key metadata.
cmd/controller/main.go	Enables cache transforms for Node and NodeSBOM in node-scan mode and disables deep-copy for read-only cache access.

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[codecov]

Codecov Report

❌ Patch coverage is 52.63158% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 49.87%. Comparing base (5adb1bd) to head (82dd15c).
⚠️ Report is 36 commits behind head on main.

Files with missing lines	Patch %	Lines
cmd/controller/main.go	0.00%	7 Missing ⚠️
internal/controller/transform.go	83.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1234      +/-   ##
==========================================
- Coverage   53.44%   49.87%   -3.57%     
==========================================
  Files          61       77      +16     
  Lines        5340     6498    +1158     
==========================================
+ Hits         2854     3241     +387     
- Misses       2088     2801     +713     
- Partials      398      456      +58     

Flag	Coverage Δ
unit-tests	49.87% <52.63%> (-3.57%)	⬇️

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[alegrey91]

LGTM. Please suppress the golangci-lint error before merging it.